Coolant loss

Midlife_crisis

Active Member
Jun 1, 2016
76
2
Hi,
I'm having issues with coolant leaking. My cupra was idling high and read that it could be the coolant temp sensor, I replaced the sensor last weekend and the idling was still high but not as high as before. Tonight I had the light on the temp gauge come on and when I got home saw that I have a leak on the Pasenger side of the engine, the side that the sensor is. I checked but the sensor seating looked dry.
Has anyone had this happen to them? Could it be that there is a air lock because of changing the sensor, or have I just desturbed something?
Thanks,
Ed
 

hombre_paulo

Active Member
Jan 12, 2013
157
3
Its common for the flange that the sensor sits in to leak where it attaches to the block. If it is you`ll see pinky crystal like stuff on top of your gearbox
 

Midlife_crisis

Active Member
Jun 1, 2016
76
2
Thanks, is it the flange itself or the gasket? Am I able to purchase it from ecp and if so what is it called.
 

Midlife_crisis

Active Member
Jun 1, 2016
76
2
Its common for the flange that the sensor sits in to leak where it attaches to the block. If it is you`ll see pinky crystal like stuff on top of your gearbox

Am I right in saying that this flange is bolted on with Allen cap bolts? Also could you tell me where the thermostat is as I might just change it while I'm working on the car seeing that I've spent so much time at ecp this week that I'm considering introducing the parts sales man to my family.:D
 

Midlife_crisis

Active Member
Jun 1, 2016
76
2
You're an absolute star hombre_paulo, I managed to get this flange off and there is pink on the hard lines that is bolted to the flange. If I can bombard you with more questions please, the o-ring that forms the gasket does seem "flat" and also very soft. Is that because of the heat or is it a kind of silicone or something similarly soft. Am I able to replace it with an o-ring that you buy in one of those o-ring kits or would I have to bend over so the stealers can have their way with me for a bit of rubber.
Thanks for your help it is appreciated.
Ed
 

tombo

Active Member
Apr 21, 2013
39
1
They do go flat once used, it's a good idea to replace - I have only ever used ones from stealer/tps.
 

Midlife_crisis

Active Member
Jun 1, 2016
76
2
New flange should come with the o ring and yes is will go flat once fitted

Balls, I only ordered the o-ring. Are you trying to say that the flange will need replacing as well, I bought a tool to remove them stupid hose clamps and the tool broke on the first one. It wasn't a cheapie either.
 

Midlife_crisis

Active Member
Jun 1, 2016
76
2
ive ordered the parts for next day delivery, Sod's law that I "just" missed the cut off for next day delivery but for £5 it will be there tomorrow. God I hate having to deal with dealers.
 

Midlife_crisis

Active Member
Jun 1, 2016
76
2
Did you get a genuine VW coolant sensor? Other brands are crap and the plastic horseshoe clips last 5 minutes

Hi, no I did not. Got one from ecp, just had to get it fixed as the idling was driving me crazy. I'll get that replaced too, thanks for the warning. Would the thermostat that I got from ecp be ok, I didn't go for the cheap option.
 

Alexis27

Active Member
Dec 20, 2009
2,099
452
Manchester
Yeah, the thermostat should be fine.

I've lost loads of coolant in the past through fitting aftermarket coolant sensors though!
 

Midlife_crisis

Active Member
Jun 1, 2016
76
2
Firstly thanks for the help. I've sorted the leak. Managed to break the tool I got for those brilliant hose clamps and got that replaced. Serviced the car while I was at it but gave up on replacing the thermostat as I didn't think of getting a replacement dipstick tube which needs removing when doing the thermostat. But then managed to break bits off the dipstick and I know of one bit that went down the tube..... Which means draining the oil again and replacing the filter which is all new and probably dropping the sump to get the plastic out. I love my car............I really do.
 

Upia

Active Member
Nov 30, 2015
137
10
Derbyshire
Those damn dipsticks eh.

I'm also loosing coolant but at a very slow rate, oil remains the same. I just can't figure out where it's going.
I have to top up coolant every 2 or 3 weeks, however it's always just below the minimum line when I get to it.

Sent from my GT-I9505 using Tapatalk
 
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Midlife_crisis

Active Member
Jun 1, 2016
76
2
Check the flange just above the gearbox, should see it on the gearbox. If it is get it from the dealers. Easy job to change but I got a tool for the hose clamps which beats having to struggle pliers.
Never have I owned a car that had issues with dipsticks, along with the leaking doors it is a brilliant but frustrating car to own. Would I have another? Of course
 

Andrewwright

Turbo lover
Aug 16, 2016
1,567
224
Peterborough
After all the years no one has made a stainless version of the dipstick and holder. I'd buy one tomorrow

Sent from my SM-G389F using Tapatalk
 
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Midlife_crisis

Active Member
Jun 1, 2016
76
2
After all the years no one has made a stainless version of the dipstick and holder. I'd buy one tomorrow

Sent from my SM-G389F using Tapatalk[/QUOTE

So would I, so annoying when it breaks. Especially when I had just changed the oil and have checked the oil numerous times without any issue.
 
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